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  <title>Generates cryptographically secure pseudo-random integers</title>
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  <div id="layout-content"><div id="function.random-int" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">random_int</h1>
  <p class="verinfo">(PHP 7)</p><p class="refpurpose"><span class="refname">random_int</span> &mdash; <span class="dc-title">Generates cryptographically secure pseudo-random integers</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.random-int-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>random_int</strong></span>
    ( <span class="methodparam"><span class="type">int</span> <code class="parameter">$min</code></span>
   , <span class="methodparam"><span class="type">int</span> <code class="parameter">$max</code></span>
   ) : <span class="type">int</span></div>

  <p class="para rdfs-comment">
   Generates cryptographic random integers that are suitable for use where
   unbiased results are critical, such as when shuffling a deck of cards for a
   poker game.
  </p>
  
<p class="para">
 The sources of randomness used for this function are as follows:
</p>
<ul class="itemizedlist">
 <li class="listitem">
  <span class="simpara">
   On Windows,
   <a href="https://msdn.microsoft.com/en-us/library/windows/desktop/aa379942(v=vs.85).aspx" class="link external">&raquo;&nbsp;<span class="function"><strong>CryptGenRandom()</strong></span></a>
   will always be used. As of PHP 7.2.0, the
   <a href="https://docs.microsoft.com/en-us/windows/desktop/SecCNG/cng-portal" class="link external">&raquo;&nbsp;CNG-API</a>
   will always be used instead.
  </span>
 </li>
 <li class="listitem">
  <span class="simpara">
   On Linux, the
   <a href="http://man7.org/linux/man_pages/man2/getrandom.2.html" class="link external">&raquo;&nbsp;getrandom(2)</a>
   syscall will be used if available.
  </span>
 </li>
 <li class="listitem">
  <span class="simpara">
   On other platforms, <var class="filename">/dev/urandom</var> will be used.
  </span>
 </li>
 <li class="listitem">
  <span class="simpara">
   If none of the aforementioned sources are available, then an
   <a href="class.exception.html" class="classname">Exception</a> will be thrown.
  </span>
 </li>
</ul>

  
 <blockquote class="note"><p><strong class="note">Note</strong>: 
  <span class="simpara">
   Although this function was added to PHP in PHP 7.0, a
   <a href="https://github.com/paragonie/random_compat" class="link external">&raquo;&nbsp;userland implementation</a>
   is available for PHP 5.2 to 5.6, inclusive.
  </span>
 </p></blockquote>

 </div>


 <div class="refsect1 parameters" id="refsect1-function.random-int-parameters">
  <h3 class="title">参数</h3>
  <dl>

   
    <dt>
<code class="parameter">min</code></dt>

    <dd>

     <p class="para">
      The lowest value to be returned, which must be
      <strong><code>PHP_INT_MIN</code></strong> or higher.
     </p>
    </dd>

   
   
    <dt>
<code class="parameter">max</code></dt>

    <dd>

     <p class="para">
      The highest value to be returned, which must be less than or equal to
      <strong><code>PHP_INT_MAX</code></strong>.
     </p>
    </dd>

   
  </dl>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.random-int-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns a cryptographically secure random integer in the range
   <code class="parameter">min</code> to <code class="parameter">max</code>, inclusive.
  </p>
 </div>


 <div class="refsect1 errors" id="refsect1-function.random-int-errors">
  <h3 class="title">错误／异常</h3>
  <ul class="itemizedlist">
   
 <li class="listitem">
  <span class="simpara">
   If an appropriate source of randomness cannot be found,
   an <a href="class.exception.html" class="classname">Exception</a> will be thrown.
  </span>
 </li>
 <li class="listitem">
  <span class="simpara">
    If invalid parameters are given, a <strong class="classname">TypeError</strong>
    will be thrown.
  </span>
 </li>

   <li class="listitem">
    <span class="simpara">
     If <code class="parameter">max</code> is less than <code class="parameter">min</code>, an
     <strong class="classname">Error</strong> will be thrown.
    </span>
   </li>
  </ul>
 </div>


 <div class="refsect1 examples" id="refsect1-function.random-int-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-887">
   <p><strong>Example #1 <span class="function"><strong>random_int()</strong></span> example</strong></p>
   <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">random_int</span><span style="color: #007700">(</span><span style="color: #0000BB">100</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">999</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">random_int</span><span style="color: #007700">(-</span><span style="color: #0000BB">1000</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
   </div>

   <div class="example-contents"><p>以上例程的输出类似于：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
int(248)
int(-898)
</pre></div>
   </div>
  </div>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.random-int-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member"><span class="function"><a href="random_bytes.html" class="function" rel="rdfs-seeAlso">random_bytes()</a> - Generates cryptographically secure pseudo-random bytes</span></li>
  </ul>
 </div>


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